In casting aluminum vehicle wheels, a comparatively large percentage thereof are sufficiently porous when cast as to leak air when a tire is mounted thereon. It is presently common to test for such air leaks by immersing the wheel casting in a water bath. The leaks detected by such water bath testing must then be sealed, generally by use of a liquid sealing compound. Where a large leak is detected, it has been proposed to peen the casting in the area of the leak. In many instances, however, it is not possible to seal a leak and the casting must be remelted. The cost of detecting and correcting air leaks adds appreciably to the cost manufacturing such vehicle wheels.